Blackberries usually ripen from late summer through the fall, and depending on which variety you’ve got in your backyard, you might be harvesting them for quite a while. But have you ever noticed some of your berries just refusing to turn that deep, glossy black? It’s a common headache for gardeners, and today I’m going to help you figure out why that’s happening.
When your berries stay “half-baked”
It’s actually pretty common to see blackberries that just won’t ripen all the way. To understand why, you have to look at how they grow. Blackberries (and raspberries) are what we call “aggregate fruits.” If you look closely, you’ll see they’re actually made up of dozens of tiny little individual fruit segments.
The main culprit behind uneven ripening is the blackberry mite (also known as the redberry mite). If these tiny pests infest your plant and snack on even just one of those little segments, that specific part of the berry will stay hard and red while the rest turns black. You end up with a “patchwork” berry that looks half-ripe. While they aren’t necessarily poisonous, most folks find them pretty unappetizing and end up tossing them.
How to tackle blackberry mites
The most effective way to protect your harvest is to get out your garden shears. If you see infested fruit or stems, prune those parts off immediately. Don’t just throw them in the compost pile, though! It’s best to burn the clippings or dispose of them in the trash to stop the mites from spreading. These little guys are hardy—they’ll hunker down and overwinter right near your plants, ready to cause trouble again next season if you don’t clear them out.
A natural DIY fix for your garden
While you can find chemical sprays at the big-box stores, I’m always a bit wary of using heavy-duty chemicals on things I plan to eat. Luckily, you can whip up a simple, organic spray right in your kitchen. Here’s what you’ll need:
- A bottle of standard canola oil
- A spray bottle with a “fine mist” setting
- Water for thinning
Mix the canola oil with enough water so that it’s thin enough to spray easily (pure oil is too thick and will just clog your nozzle). Give the mixture a good shake and spray it directly onto the young shoots of your blackberry plants. The oil works by suffocating the mites. Pro tip: Make sure to treat any neighboring plants as well, otherwise the mites will just hop back over to your berries once the coast is clear!
